1. Field of the Invention
This invention pertains to the field of planned maintenance and repair of components used in an assembly or collection of assemblies, such as an aircraft fleet, and more particularly, to a method and system of forecasting unscheduled component demand for such assemblies.
2. Description of the Related Art
The following terminology will be used throughout this application:    Assembly—a device or apparatus that includes a plurality of an individually replaceable and/or repairable portions;            Component (a.k.a. “part”)—an individually replaceable and/or repairable portion of an assembly;        Fleet—collection of assemblies;        Part number—a unique identifier of an individual component included in an assembly;        Serviceable part—a particular component that can be used to replace a like component in an assembly;        Unserviceable part—a particular component that is in need of repair.        
In the airline industry, a well-organized system and process for performing maintenance of an aircraft fleet is critical. Regularly scheduled routine maintenance of the aircraft fleet is carefully planned to meet governmental and company-established airline safety requirements, to minimize any disruption to revenue-generating flight schedules, and to contain inventory costs.
A typical aircraft fleet may consist of more than a dozen different types of aircraft (e.g., 18) having thousands of different types of components (e.g., more than 6700), and scheduled maintenance may be performed at dozens of different maintenance facilities located throughout the world.
FIG. 1 illustrates an exemplary arrangement of maintenance and repair facilities for an aircraft fleet. In a typical arrangement, an airline may have one or more centrally located maintenance facilities 110 for performing major routine scheduled maintenance jobs on the aircraft and/or components thereof. The airline also may have several satellite maintenance facilities 120, located at a number of different locations throughout its service area, for performing routine scheduled maintenance jobs. Typically, one or more repair depots 130 receive unserviceable parts from the various maintenance facilities 110, 120 and repair the unserviceable parts to produce serviceable parts. The serviceable parts are then kept in one or more central warehouses or stores 140 from which they are distributed to the maintenance facilities 110, 120.
To perform regularly scheduled routine maintenance, the proper serviceable parts must be made available at the various maintenance facilities 110, 120 at the scheduled time. Failure to have these serviceable parts available when and where they are needed can delay the scheduled maintenance, resulting in postponements or cancellations of revenue-generating flights. On the other hand, it is not cost effective to keep excess inventories of serviceable parts at each maintenance facility 110, 120 where routine maintenance is performed, or in the central stores 140.
Therefore, component repair schedules for the repair depot(s) 130 are carefully devised, considering many factors, including: the known routine maintenance schedules for all of the aircraft in the fleet; the locations of the maintenance facilities where the routine maintenance will be performed; the various components of each aircraft which will be replaced during the scheduled maintenance visits; the different personnel which are qualified to repair the various components; the typical time period required to repair each component; etc. Computer software has been developed to automate the process of preparing schedules for repairing the components needed for routine scheduled maintenance of the aircraft in the fleet.
However, routine scheduled maintenance is only one component of the overall problem of aircraft maintenance. The other major component is unscheduled, non-routine aircraft maintenance required by unexpected component failure. Unscheduled, non-routine aircraft maintenance in turn creates unscheduled component demand for serviceable parts.
Recently, it has been determined that as much as 80% of all component demand in an airline maintenance system is unscheduled component demand! Therefore, if such unscheduled component demand is not accounted for in the preparation of component repair schedules, serviceable parts will not be available when and where they are needed to perform unscheduled, non-routine aircraft maintenance. As noted above, the failure to have serviceable parts available when and where they are needed in turn will cause postponements or cancellations of revenue-generating flights.
However, until now there has not been a system or method for effectively or accurately forecasting and planning for such unscheduled component demand.
Meanwhile, it is also desired to produce a detailed work schedule for the repair depots 130. Such a detailed work schedule should preferably establish the exact order in which components are to be repaired. Ideally, a system and method for producing such a component repair schedule would instruct a component repair specialist as to exactly which component should be repaired next in order to optimize the availability of serviceable parts for the aircraft fleet. Such a system and method needs to consider many factors to produce the component repair schedule, including: a forecast of all unscheduled component demand for the aircraft fleet; the known routine maintenance schedules for all of the aircraft in the fleet; the locations of the maintenance facilities where the routine maintenance will be performed; the various components of each aircraft which will be replaced during the scheduled maintenance visits; the different personnel which are qualified to repair the various components; the typical time period required to repair each component; etc.
Similar problems to those described above exist in other industries and situations, for example: a trucking company having a fleet of trucks; a Navy having a fleet of ships; an emergency services (e.g., police) two-way radio communication system; an electric utility, a large computer network; etc. All of these situations, and others, could benefit from a system and method for effectively or accurately forecasting and planning for unscheduled component demand.
Accordingly, it would be advantageous to provide a system and method for effectively or accurately forecasting and planning for such unscheduled component demand. It would also be advantageous to provide a system and method for producing a component repair schedule that accounts for unscheduled component demand. Other and further objects and advantages will appear hereinafter.